Tools for following the normal of a surface can be used to guide a welding torch for the welding of metal plates, for example, to produce a sealed tank wall.
Such a sealed tank is obtained by welding together metal parts which have a common profile. FR2701415 describes an automatic machine which is capable of producing welds following the profile common to the metal parts to produce such a tank wall.
Such a machine comprises a support that is fixed relative to the parts to be assembled. A carriage is mounted on this fixed support and moves along an advance trajectory. This carriage bears a welding torch which can produce spot welds or weld beads. This torch can move in rotation and in translation relative to the robot. The rotational and translational mobility of the torch is controlled by a control device. This control device is in turn connected to detection means on the carriage which measure the position of the torch relative to the surface. The control device transmits control signals to actuators according to the position transmitted by the detection means. Based on these control signals, these actuators orientate and position the torch relative to the metal parts.
The abovementioned detection means can be, for example, a laser range finder, an inductive detector or a capacitive detector. However, this type of automatic machine requires computation means to determine the tangent to the profile and thus orient the welding torch according to this tangent. Furthermore, these types of detection means are costly and can even be sensitive to electromagnetic disturbances.
DE-U-2514415 describes a reproduction probe for a milling machine which comprises a fixing rod, a probe mounted to pivot thereon and an abutment on the free end of the probe.